Server hang with semaphore deadlock between the between a database and collection semaphore when running 3rd party application

Technote (troubleshooting)

Problem

The Domino server hangs due to a semaphore deadlock.

Symptom

Semaphore deadlock condition

Cause

The 3rd party application's extension handle of MBEServer4051 is calling to open a collections while being used by AddFolderOp causing the dead lock if an update thread, held collection sem, tried to update the collection will be waiting for the database sem. It should not try to open a collection through extension manager while holding on to database semaphore